Robot cleaner

CROSS-REFERENCE TO RELATED APPLICATIONS

p-0002This application claims the benefit of Korean Patent Application No. 2011-0099648, filed on Sep. 30, 2011 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

p-00031. Field

p-0004Embodiments of the present disclosure relate to a robot cleaner having an improved configuration to enable implementation of a cleaning operation without interruption of travel.

p-00052. Description of the Related Art

p-0006In general, a robot cleaner is an apparatus that automatically cleans a target area to be cleaned by suctioning impurities, such as dust, etc., from a floor while autonomously traveling about the area without user intervention.

p-0007The robot cleaner functions to detect a distance from an obstacle, such as furniture, office appliances and walls, present in the cleaning area using a variety of sensors, and to clean the target area while traveling without collision with the obstacle based on detected information.

p-0008Cleaning a given cleaning area using the robot cleaner means an operation in which the robot cleaner repeatedly performs a cleaning operation while traveling in the cleaning area based on a preset traveling pattern.

p-0009Obstacles present in a cleaning area where the robot cleaner travels include an obstacle, such as a doorsill, that the robot cleaner must pass over.

p-0010When passing over, e.g., the doorsill present in the cleaning area, however, the center of the robot cleaner may be caught by the doorsill, causing separation of a wheel, and consequently interruption of travel of the robot cleaner.

SUMMARY

p-0011Therefore, it is one aspect of the present disclosure to provide a robot cleaner having a configuration to enable implementation of a cleaning operation without interruption of travel due to an obstacle present in a cleaning space when the robot cleaner passes over the obstacle.

p-0012Additional aspects of the disclosure will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosure.

p-0013In accordance with one aspect of the present disclosure, a robot cleaner includes a main body and drive devices installed respectively at left and right peripheral positions on the basis of the center of the main body to drive the main body, wherein each of the drive devices includes a main wheel to drive the main body, a drive motor to generate rotation power required to rotate the main wheel, a gear assembly to transmit rotation power of the drive motor to the main wheel, a drive shaft to interconnect the gear assembly and the main wheel so as to assist the main wheel in rotating by rotation power transmitted from the gear assembly, the drive shaft extending from the main wheel toward the center of the main body, and an auxiliary wheel to drive the main body, the auxiliary wheel being connected to a distal end of the drive shaft extending toward the center of the main body so as to be located closer to the center of the main body than the main wheel, and wherein, if the main wheel is lifted from a floor as the main body is caught at the center thereof by an obstacle when passing over the obstacle during traveling, the auxiliary wheel protrudes downward of the main body to reach the floor, assisting the main body in traveling to escape from the obstacle.

p-0014The main body may include a main brush to sweep or scatter dust present in a cleaning space, thus achieving improved dust suction efficiency, and the main brush may be installed between the main wheels at a rear bottom region of the main body.

p-0015The main brush may extend by a long length such that left and right ends of the main brush are located close to the rim of the main body to ensure that the main brush cleans a wide cleaning space via one revolution thereof.

p-0016The main wheels may be installed close to left and right rim positions of the main body to allow the left and right ends of the main brush between the main wheels to be located close to the rim of the main body, and the gear assembly may be installed between a corresponding one of the main wheels and the center of the main body.

p-0017The drive device may include a housing in which the main wheel and the gear assembly are received, and the housing may have an open bottom to enable upward and downward movement of the main wheel.

p-0018The housing may have a first coupling hole for insertion of a rotating shaft of the drive motor, and the gear assembly may have a second coupling hole for insertion of the rotating shaft inserted into the first coupling hole.

p-0019The housing may have a first coupling boss aligned on the same axis as the rotating shaft so as to be coupled to the gear assembly, the gear assembly may have a second coupling boss to couple the gear assembly to the housing, and the first coupling boss may have a receiving hole in which the second coupling boss is pivotally received such that the gear assembly is pivotable about the first coupling boss.

p-0020The gear assembly may have a third coupling hole for insertion of the drive shaft, and the housing may have a guide slot for penetration of the drive shaft inserted into the third coupling hole, whereby the drive shaft having passed through the guide slot extends toward the center of the main body.

p-0021The auxiliary wheel may be connected to a distal end of the drive shaft penetrating the guide slot, and may be located outside of the housing.

p-0022The main wheel, the gear case and the auxiliary wheel, which are connected to one another via the drive shaft, may be moved upward and downward via rotation thereof about the rotating shaft of the drive motor, and the guide slot may guide rotation of the drive shaft about the rotating shaft.

p-0023An outer diameter of the auxiliary wheel may be less than an outer diameter of the main wheel.

p-0024In accordance with another aspect of the present disclosure, a robot cleaner includes a main body, a main brush installed at a rear bottom region of the main body, and drive devices installed respectively at left and right peripheral positions on the basis of the center of the main body to drive the main body, wherein each of the drive devices includes a main wheel to drive the main body, a drive motor to generate rotation power required to rotate the main wheel, a gear assembly to transmit rotation power of the drive motor to the main wheel, a drive shaft to interconnect the gear assembly and the main wheel so as to assist the main wheel in rotating by rotation power transmitted from the gear assembly, and an auxiliary wheel connected to the drive shaft to drive the main body, the auxiliary wheel being located closer to the center of the main body than the main wheel, and wherein the main wheel is located closer to the rim of the main body than the gear assembly to allow the main brush between the main wheels to extend by a long length such that left and right ends of the main brush are located close to the rim of the main body.

p-0025If the main wheel is lifted from a floor as the main body is caught at the center thereof by an obstacle when passing over the obstacle during traveling, the auxiliary wheel may protrude downward of the main body to reach the floor, assisting the main body in traveling to escape from the obstacle.

p-0026The drive device may include a housing in which the main wheel and the gear assembly are received, and the housing may have an open bottom to enable upward and downward movement of the main wheel.

p-0027The housing may have a first coupling hole for insertion of a rotating shaft of the drive motor, and the gear assembly may have a second coupling hole for insertion of the rotating shaft inserted into the first coupling hole.

p-0028The housing may have a first coupling boss aligned on the same axis as the rotating shaft so as to be coupled to the gear assembly, the gear assembly may have a second coupling boss to couple the gear assembly to the housing, and the first coupling boss may have a receiving hole in which the second coupling boss is pivotally received such that the gear assembly is pivotable about the first coupling boss.

p-0029The gear assembly may have a third coupling hole for insertion of the drive shaft, and the housing may have a guide slot for penetration of the drive shaft inserted into the third coupling hole, whereby the drive shaft having passed through the guide slot extends toward the center of the main body.

p-0030The auxiliary wheel may be connected to a distal end of the drive shaft penetrating the guide slot, and may be located outside of the housing.

p-0031The main wheel, the gear case and the auxiliary wheel, which are connected to one another via the drive shaft, may be moved upward and downward via rotation thereof about the rotating shaft of the drive motor, and the guide slot may guide rotation of the drive shaft about the rotating shaft.

p-0032An outer diameter of the auxiliary wheel may be less than an outer diameter of the main wheel.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0033These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

p-0034<figref idrefs="DRAWINGS">FIG. 1</figref> is a perspective view showing a configuration of a robot cleaner according to an embodiment of the present disclosure;

p-0035<figref idrefs="DRAWINGS">FIG. 2</figref> is a bottom view of the robot cleaner according to the embodiment of the present disclosure;

p-0036<figref idrefs="DRAWINGS">FIG. 3</figref> is a perspective view showing a drive device of the robot cleaner according to the embodiment of the present disclosure;

p-0037<figref idrefs="DRAWINGS">FIG. 4</figref> is an exploded perspective view of the drive device shown in <figref idrefs="DRAWINGS">FIG. 3</figref>;

p-0038<figref idrefs="DRAWINGS">FIGS. 5 to 8</figref> are views showing an up-and-down movement of a main wheel and an auxiliary wheel of the drive device shown in <figref idrefs="DRAWINGS">FIG. 3</figref>; and

p-0039<figref idrefs="DRAWINGS">FIG. 9</figref> is a view showing a state when the auxiliary wheel of the robot cleaner according to the embodiment of the present disclosure passes over an obstacle.

DETAILED DESCRIPTION

p-0040Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

p-0041As shown in <figref idrefs="DRAWINGS">FIGS. 1 and 2</figref>, a robot cleaner <b>1</b> includes a main body <b>10</b> defining the external appearance of the robot cleaner, a cover <b>20</b> configured to cover the top of the main body <b>10</b>, a brush unit <b>30</b> configured to sweep or scatter dust present in a cleaning space, a power unit <b>40</b> to supply power required to drive the main body <b>10</b>, and drive devices <b>100</b> to drive the main body <b>10</b>.

p-0042The main body <b>10</b> defines the external appearance of the robot cleaner <b>1</b> and supports a variety of elements mounted in the robot cleaner <b>1</b>.

p-0043The cover <b>20</b> includes a transparent window <b>21</b> to transmit light emitted from an upward camera (not shown) that captures an image of an upper space perpendicular to a traveling direction of the main body <b>10</b>.

p-0044The brush unit <b>30</b> includes a main brush <b>31</b> fitted into a suction opening <b>11</b> that is perforated in a rear region of a bottom surface of the main body <b>10</b>, a main brush motor <b>33</b> to rotate the main brush <b>31</b>, and a dust container <b>35</b> into which impurities, such as dust, swept by the main brush <b>31</b>, are collected.

p-0045The main brush <b>31</b> serves to sweep or scatter dust on a floor below the main body <b>10</b>, improving dust suction efficiency.

p-0046The main brush <b>31</b> has a drum shape and consists of a roller <b>31</b><i>a </i>and a brush <b>31</b><i>b. </i>

p-0047To ensure that the main brush <b>31</b> cleans a wide cleaning space via one revolution thereof, it may be necessary to provide the main brush <b>31</b> with a long length such that left and right ends of the main brush <b>31</b> are close to the rim of the main body <b>10</b>.

p-0048Since the main brush <b>31</b> is located between main wheels <b>120</b> of the drive devices <b>100</b> that will be described hereinafter, provision of the long main brush <b>31</b> may require an increase in a distance between the main wheels <b>120</b> that are mounted to left and right peripheral positions of the main body <b>10</b> on the center axis thereof.

p-0049To increase the distance between the main wheels <b>120</b> to the maximum extent, it may be necessary to locate the main wheels <b>120</b> of the drive device <b>100</b> toward an outermost portion of the main body <b>10</b>.

p-0050To install the main wheels <b>120</b> close to the outermost portion, i.e. the rim of the main body <b>10</b>, a gear assembly <b>140</b> of each drive device <b>100</b> may be located closer to the center of the main body <b>10</b> than the main wheels <b>120</b>.

p-0051Although not shown, the brush unit <b>30</b> may further include side brushes that are arranged at opposite sides of the main brush <b>31</b> to sweep dust on a place where the main brush <b>31</b> does not reach, improving cleaning efficiency.

p-0052The power unit <b>40</b> includes a battery <b>41</b>, which is electrically connected to drive motors <b>130</b> that rotates the main wheels <b>120</b> and auxiliary wheels <b>160</b>, the main brush motor <b>33</b> that rotates the main brush <b>31</b>, and other drive devices that drive the main body <b>10</b> to supply power thereto.

p-0053The battery <b>41</b> is a rechargeable secondary battery, and is charged with power supplied from a docking station (not shown) when the main body <b>10</b> is docked with the docking station (not shown) after completion of a cleaning operation.

p-0054The drive devices <b>100</b> are located at opposite sides of the center of the main body <b>10</b> and enable advancement, reverse travel, rotation, and other movements of the main body <b>10</b> during traveling thereof.

p-0055The following description is centered on the drive device <b>100</b> located at the right side on the basis of an advancement direction of the main body <b>10</b> by way of example, and is equally applied even to the drive device <b>100</b> located at the left side on the basis of the advancement direction of the main body <b>10</b> so long as it is not specially mentioned.

p-0056As shown in <figref idrefs="DRAWINGS">FIGS. 3 and 4</figref>, the drive device <b>100</b> includes a housing <b>110</b>, the main wheel <b>120</b> to drive the main body <b>10</b> during normal travel, the drive motor <b>130</b> coupled to one side of the housing <b>110</b> to rotate the main wheel <b>120</b>, the gear assembly <b>140</b> placed between the main wheel <b>120</b> and the drive motor <b>130</b> to transmit drive power of the drive motor <b>130</b> to the main wheel <b>120</b>, a drive shaft <b>150</b> extending on the center axis of the main body <b>10</b> to interconnect the main wheel <b>120</b> and the gear assembly <b>140</b> such that the main wheel <b>120</b> is rotated by rotation power transmitted from the gear assembly <b>140</b>, and an auxiliary wheel <b>160</b> connected to a distal end of the drive shaft <b>150</b> toward the center of the main body <b>10</b> to drive the main body <b>10</b> during abnormal travel.

p-0057The housing <b>110</b> includes a receiver <b>111</b> in which the main wheel <b>120</b> and the gear assembly <b>140</b> are received, a first coupling hole <b>113</b> for coupling of the drive motor <b>130</b>, a first coupling boss <b>115</b> for coupling of the gear assembly <b>140</b>, a first support protrusion <b>117</b> fitted into one end of an elastic member <b>170</b>, and a guide slot <b>119</b> through which the drive shaft <b>150</b> penetrates so as to extend toward the center of the main body <b>10</b>.

p-0058The receiver <b>111</b> has an open bottom such that the gear assembly <b>140</b> coupled to the housing <b>110</b> and the main wheel <b>120</b> coupled to the gear assembly <b>140</b> are movable up and down according to the kind and state of the floor in the cleaning area.

p-0059The first coupling hole <b>113</b> is formed in one sidewall <b>110</b><i>b </i>of the housing <b>110</b> to assist a rotating shaft <b>131</b> of the drive motor <b>130</b> in being coupled to the gear assembly <b>140</b> within the housing <b>110</b>.

p-0060The first coupling boss <b>115</b> protrudes inward of the housing <b>110</b> by a predetermined length from an inner surface of the other sidewall <b>110</b><i>a </i>that is opposite to the sidewall <b>110</b><i>b </i>of the housing <b>110</b> to which the drive motor <b>130</b> is coupled.

p-0061The first coupling boss <b>115</b> has a center receiving hole <b>115</b><i>a </i>in which a second coupling boss <b>145</b> of the gear assembly <b>140</b> is pivotally received, such that the gear assembly <b>140</b> is pivotable about the first coupling boss <b>115</b>.

p-0062The first coupling boss <b>115</b> may be located on the same axis as the first coupling hole <b>113</b> and the rotating shaft <b>131</b> of the drive motor <b>130</b> that penetrates the first coupling hole <b>113</b>.

p-0063Once the first coupling boss <b>115</b> has been located on the same axis as the rotating shaft <b>131</b> of the drive motor <b>130</b>, the gear assembly <b>140</b> is pivotable about the rotating shaft <b>131</b> of the drive motor <b>130</b>.

p-0064The first support protrusion <b>117</b> protrudes inward of the housing <b>110</b> by a predetermined length from an inner surface of the sidewall <b>110</b><i>b </i>of the housing <b>110</b> to which the drive motor <b>130</b> is coupled. The first support protrusion <b>117</b> is fitted into one end of the elastic member <b>170</b> that elastically supports the gear assembly <b>140</b>.

p-0065The guide slot <b>119</b> is formed in the sidewall <b>110</b><i>b </i>of the housing <b>110</b> such that the drive shaft <b>150</b> penetrates the guide slot <b>119</b> to thereby extend toward the center of the main body <b>10</b>. The guide slot <b>119</b> provides a movement path along which the drive shaft <b>150</b>, to which the main wheel <b>120</b>, the gear assembly <b>140</b> and the auxiliary wheel <b>160</b> that will be described hereinafter are coupled, is movable to pivot about the first coupling boss <b>115</b>.

p-0066The main wheel <b>120</b> is installed to come into direct contact with the floor in the cleaning space so as to enable traveling of the main body <b>10</b>. The main wheel <b>120</b> is connected to the gear assembly <b>140</b> via the drive shaft <b>150</b> and is rotated upon receiving rotation power transmitted from the gear assembly <b>140</b>.

p-0067The drive motor <b>130</b> is coupled to an outer surface of the sidewall <b>110</b><i>b </i>of the housing <b>110</b> in which the first coupling hole <b>113</b> is formed. The rotating shaft <b>131</b> of the drive motor <b>130</b> penetrates the first coupling hole <b>113</b> to thereby be coupled to the gear assembly <b>140</b> within the housing <b>110</b>.

p-0068As drive power of the drive motor <b>130</b> is transmitted to the drive shaft <b>150</b> via the rotating shaft <b>131</b> and power-transmission gears <b>142</b> connected to the rotating shaft <b>131</b>, rotation of the main wheel <b>120</b> is accomplished.

p-0069The gear assembly <b>140</b> includes a gear case <b>141</b>, power-transmission gears <b>142</b> rotatably engaged with each other within the gear case <b>141</b>, the second coupling boss <b>145</b> to couple the gear assembly <b>140</b> and the housing <b>110</b> to each other, and a second support protrusion <b>148</b> fitted into the other end of the elastic member <b>170</b>.

p-0070The gear case <b>141</b> rotatably supports the power-transmission gears <b>142</b> therein.

p-0071The power-transmission gears <b>142</b> are rotatably supported by the gear case <b>141</b> while being engaged with each other. The power-transmission gears <b>142</b> interconnect the rotating shaft <b>131</b> of the drive motor <b>130</b> and the drive shaft <b>150</b> to transmit drive power of the drive motor <b>130</b> to the drive shaft <b>150</b>.

p-0072The rotating shaft <b>131</b> may penetrate a second coupling hole <b>143</b> formed in one side <b>141</b> b of the gear case <b>141</b> to thereby be connected to one of the power-transmission gears <b>142</b>. The drive shaft <b>150</b> may penetrate a third coupling hole <b>144</b> formed in the other side <b>141</b><i>a </i>of the gear case <b>141</b> to thereby be connected to one of the other power-transmission gears <b>142</b> that are not coupled to the rotating shaft <b>131</b>.

p-0073The second coupling boss <b>145</b> protrudes, by a predetermined length, from the other side <b>141</b><i>a </i>of the gear case <b>141</b> toward the first coupling boss <b>115</b> and is rotatably fitted into the receiving hole <b>115</b><i>a </i>formed in the first coupling boss <b>115</b>.

p-0074The second support protrusion <b>148</b> protrudes from an upper end of the gear case <b>141</b> toward the first support protrusion <b>117</b> to thereby be fitted into the other end of the elastic member <b>170</b> that elastically supports the gear assembly <b>140</b>.

p-0075The gear assembly <b>140</b> is pivotally coupled to the housing <b>110</b> via the second coupling boss <b>145</b>, and is elastically supported by the housing <b>110</b> via the second support protrusion <b>148</b> and the elastic member <b>170</b>.

p-0076The drive shaft <b>150</b> is connected to the gear assembly <b>140</b> while being fixed to the main wheel <b>120</b> to enable rotation of the main wheel <b>120</b>. The drive shaft <b>150</b> interconnecting the main wheel <b>120</b> and the gear assembly <b>140</b> extends through the housing <b>110</b> toward the center of the main body <b>10</b>.

p-0077The auxiliary wheel <b>160</b> that will be described hereinafter is coupled to the distal end of the drive shaft <b>150</b> toward the center of the main body <b>10</b>.

p-0078The main wheel <b>120</b> and the auxiliary wheel <b>160</b> interconnected by the drive shaft <b>150</b> are rotated together by drive power of the drive motor <b>130</b>. As shown in <figref idrefs="DRAWINGS">FIGS. 5 and 6</figref>, the main wheel <b>120</b> and the auxiliary wheel <b>160</b> may move up and down by pivoting about the first coupling boss <b>115</b>.

p-0079The auxiliary wheel <b>160</b> is connected to the distal end of the drive shaft <b>150</b> extending toward the center of the main body <b>10</b> fixed to the main wheel <b>120</b>, thereby being rotated along with the main wheel <b>120</b>.

p-0080The auxiliary wheel <b>160</b> is connected to the distal end of the drive shaft <b>150</b> that penetrates the housing <b>110</b> to thereby extend toward the center of the main body <b>10</b>. Thus, the auxiliary wheel <b>160</b> is located outside of the housing <b>110</b>.

p-0081Although not shown in the drawings, the auxiliary wheel <b>160</b> may be located inside the housing <b>110</b>.

p-0082Since the auxiliary wheel <b>160</b> is located outside of the housing <b>110</b>, to allow the auxiliary wheel <b>160</b> to move up and down along with the main wheel <b>120</b> that is moved up and down within the housing <b>110</b>, the main body <b>10</b> is provided at the bottom thereof with an auxiliary hole <b>113</b> for upward and downward movement of the auxiliary wheel <b>160</b>.

p-0083The auxiliary wheel <b>160</b> may have an outer diameter less than that of the main wheel <b>120</b>. This ensures that the auxiliary wheel <b>160</b> does not protrude downward of the main body <b>10</b> during normal travel of the robot cleaner <b>1</b>.

p-0084As shown in <figref idrefs="DRAWINGS">FIGS. 5 and 6</figref>, during normal travel of the robot cleaner <b>1</b>, the auxiliary wheel <b>160</b> does not protrude downward of the main body <b>10</b>, and therefore the robot cleaner <b>1</b> is driven by the main wheel <b>120</b>.

p-0085However, if the robot cleaner <b>1</b> is no longer driven by the main wheel <b>120</b> as the center of the main body <b>10</b> is caught by an obstacle, such as a doorsill, etc., during traveling of the robot cleaner <b>1</b>, the auxiliary wheel <b>160</b> is moved to protrude downward of the main body <b>10</b> so as to drive the robot cleaner <b>1</b>.

p-0086Considering driving of the robot cleaner <b>1</b> by the auxiliary wheel <b>160</b> as described above, as shown in <figref idrefs="DRAWINGS">FIGS. 7 to 9</figref>, if the center of the main body <b>10</b> is caught by an obstacle, such as a doorsill, etc., as the robot cleaner <b>1</b> passes over the obstacle during traveling, the main wheel <b>120</b> of the robot cleaner <b>1</b> is lifted to the air rather than touching the floor.

p-0087Once the main wheel <b>120</b> does not come into contact with the floor, the auxiliary wheel <b>160</b> connected to the main wheel <b>120</b> via the drive shaft <b>150</b> is rotated clockwise about the first coupling boss <b>115</b> of the housing <b>110</b> along with the main wheel <b>120</b>, thereby protruding downward of the main body <b>10</b>.

p-0088Since the auxiliary wheel <b>160</b> is located closer to the center of the main body <b>10</b> than the main wheel <b>120</b>, even if the center of the main body <b>10</b> is caught by the obstacle and does not come into contact with the floor, the auxiliary wheel <b>160</b> protruding downward of the main body <b>10</b> may reach the floor. As such, the robot cleaner <b>1</b> may escape from the obstacle by driving of the auxiliary wheel <b>160</b> coming into contact with the floor.

p-0089Once the robot cleaner <b>1</b> has escaped from the obstacle, the main wheel <b>120</b> reaches the floor, and then is moved upward by rotating counterclockwise about the first coupling boss <b>115</b> of the housing <b>110</b>. The auxiliary wheel <b>160</b> connected to the main wheel <b>120</b> via the drive shaft <b>150</b> is also moved upward by rotating counterclockwise about the first coupling boss <b>115</b> of the housing <b>110</b> along with the main wheel <b>120</b>, and thus no longer protrudes downward of the main body <b>10</b>.

p-0090As is apparent from the above description, a robot cleaner according to the embodiments of the present disclosure may stably perform a cleaning operation without interruption of travel while the robot cleaner passes over an obstacle, such as a doorsill, etc., present in a cleaning space.

p-0091Although the above description is centered on the specific shape and movement direction of the robot cleaner with reference to the accompanying drawings, it would be appreciated by those skilled in the art that various changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.